Toán

D

dark_gialai

Cho S(x) = 1+x+x^2+...+x^2011=x^2012-1/x-1 ;(x khác 1). Tính P(x)= 1+2x+3x^2+...+2011x^2010
[TEX]ta\ co :P(x) = S'(x) [/TEX]


[TEX]<=>S'(x) = (\frac{x^2012 -1}{x - 1})' =0 + 1 +2x+ 3x^2 +...+2011x^{2010}[/TEX]


[TEX]<=> P(x) = (\frac{x^2012 -1}{x - 1})' [/TEX]


[TEX]ban\ tu\ tinh\ dao\ ham\ duoc[/TEX]
 
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